Martian waves

A piece of Mars: The swirly candy stripes in these big dark dunes are layers inside that have been made visible by wind erosion (the scene is 1.5×0.9 km, or 0.93×0.56 mi). It’s rare to see the inside structure of dunes like this, but these are being eroded by wind blowing from the upper right. For similar examples on Earth, check out The Wave. (HiRISE ESP_037200_1765, NASA/JPL/Univ. of Arizona)